Water Demand of Concrete Recycled Aggregates

Kubissa, Jacek; Koper, Marcin; Koper, Włodzimierz; Kubissa, Wojciech; Koper, Artur

doi:10.1016/j.proeng.2015.06.120

Cited by 18 publications

(13 citation statements)

References 3 publications

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“…Absorbability of concrete with coarse aggregate substitution by RCA is presented in Figure 18. Similar results are reported by [81,82,85] for crushed RCA created without addition of any waste.…”

Section: Water Absorbabilitysupporting

confidence: 88%

“…It is connected to higher water absorbability of RCA in comparison to natural gravel. Similar results are reported by [81] for crushed RCA created without addition of any waste-water demand of RCA is significantly higher than for natural aggregates. Deterioration of consistency in lower range for both crushed ceramic waste and RCA is reported by [82][83][84].…”

Section: Consistencysupporting

confidence: 87%

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Properties of Concrete with Recycled Concrete Aggregate Containing Metallurgical Sludge Waste

et al. 2020

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Sand has been considered to be something of an immeasurable quantity. There are many indications that this view is no longer valid and that the limiting of natural aggregates usage is doubly justified. Firstly, the extraction of natural aggregates is expensive and has a huge impact on the environment. The main issues in sand and gravel mining are the large areas that are affected, ground water level changes, illegal mining, unsuitability of desert and marine sand, and costs of transport. Secondly, metallurgical waste can be used as a substitute for natural aggregates. This is doubly beneficial—the waste is recycled and the use of natural aggregates is reduced. Waste is stored in landfills that take up large areas and there is also the possibility of ground and groundwater pollution by hazardous compounds. The research presented in this article focuses on the technological conditions of using metallurgical waste in its original form and as a component of recycled concrete aggregate (RCA). The use of metallurgical sludge waste or crushed or round RCA to produce concrete deteriorates the consistency and does not significantly affect the air content and density of the concrete mix. RCA lowers the density of hardened concrete. Metallurgical sludge waste or RCA usage adversely affect the absorbability and permeability of concrete. Concrete containing metallurgical sludge waste is of higher compressive strength after 7 and 28 days, with up to 60% of waste as a sand replacement. RCA concrete achieved higher compressive strength also.

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Section: Water Absorbabilitysupporting

confidence: 88%

Section: Consistencysupporting

confidence: 87%

Properties of Concrete with Recycled Concrete Aggregate Containing Metallurgical Sludge Waste

et al. 2020

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“…The accurate determination for the water content of SFRCAC with different RCA and steel fibers to achieve target slump is the objective of this part. More water is required in the batching process to obtain the similar slump for RCAC as NCAC due to the higher water absorption of RCA [21,36,37]. The slump of concrete has been found to decrease with the increase of aspect ratio and volume fraction of steel fiber [38].…”

Section: Methodsmentioning

confidence: 99%

Mixture Proportion Design Method of Steel Fiber Reinforced Recycled Coarse Aggregate Concrete

et al. 2019

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Steel fiber reinforced recycled coarse aggregate concrete (SFRCAC) is an impact minimisation building material. Mixture proportion design method of SFRCAC is developed in this paper to obtain concrete with target strength and workability, which can be used in structural members. Four key parameters of mixture proportioning, steel fiber content, water-cement ratio, water content and sand ratio are discussed through the mixture design tests. The formula for calculating the four key parameters of mixture proportions for SFRCAC are established through the statistical analysis of test results, which mainly consider the influences of recycled coarse aggregate (RCA) replacement ratio and steel fiber characteristic coefficient. The detailed procedure by using the new mixture proportion design method is illustrated with examples. The formulas established have the simple form, reflect the properties of RCA and steel fibers, enhance the mixture proportion design accuracy, and provide the reference for the mix proportion design of SFRCAC.

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“…Some national standards (EN 206/CN, 2014) allow total or partial replacement of coarse natural aggregates with coarse recycled ones in the production of new concrete, while the fine recycled aggregates are still not widely used due to their negative effect on both workability and durability of concrete mixes (Cuenca-Moyano et al, 2014;Khatib, 2005;Zhang et al, 2018;Zega and Di Maio, 2011). In particular, the recycled sand requires a large amount of water to assure the workability, which will increase the water to cement ratio (W/C) and, consequently, will affect the mechanical properties of concrete (Khatib, 2005;Kou and Poon, 2009;Kubissa et al, 2015;Rao et al, 2007). Kubissa et al (2015) correlated the water demand of concrete recycled aggregates with the aggregates resistance to crushing whose measure is a crushing indicator.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the recycled sand requires a large amount of water to assure the workability, which will increase the water to cement ratio (W/C) and, consequently, will affect the mechanical properties of concrete (Khatib, 2005;Kou and Poon, 2009;Kubissa et al, 2015;Rao et al, 2007). Kubissa et al (2015) correlated the water demand of concrete recycled aggregates with the aggregates resistance to crushing whose measure is a crushing indicator. They established that a 1% increase in the crushing indicator results in an increase of 0.0073 dm 3 demand of water by kilogram of recycled aggregates.…”

Section: Introductionmentioning

confidence: 99%

Formulation parameters effects on the performances of concrete equivalent mortars incorporating different ratios of recycled sand

Ghorbel

Gomart

Matar

2019

Journal of Building Physics

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The present research investigates the feasibility of manufacturing masonry mortars with recycled sand. The primary aim is to study the effect of fine recycled aggregates on fresh and hardened states with properties. Two series of mortars were designed by substituting natural sand with recycled sand, with variable sand replacement ratios ranging from 0% to 100%. One series, named variable workability series, has variable workability with constant water to cement ratio ( W/C), while the other series, called constant workability series, has a constant workability with variable W/C. The density, air content, and slump of mortars in fresh state were measured with a special attention devoted to the effect of pre-saturation of recycled sand on the slump. In the hardened state, the microstructure was studied by means of water accessible porosity test and mercury intrusion porosimetry test. Flexural and compressive strength as well as the dynamic modulus of elasticity were also examined and the correlations between these properties and the microstructure have been established. It was found that the properties of mortars with recycled sand are lower than those obtained for the natural sand mortar (−20% for variable workability series and −45% for constant workability series at the age of 28 days). For the series with variable workability, mechanical properties decrease to a step starting from 30% replacement ratio, while linearly decrease for the mortars with constant workability. The difference between the two series lies in the difference in total porosities and the pore size distribution.

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Water Demand of Concrete Recycled Aggregates

Cited by 18 publications

References 3 publications

Properties of Concrete with Recycled Concrete Aggregate Containing Metallurgical Sludge Waste

Properties of Concrete with Recycled Concrete Aggregate Containing Metallurgical Sludge Waste

Mixture Proportion Design Method of Steel Fiber Reinforced Recycled Coarse Aggregate Concrete

Formulation parameters effects on the performances of concrete equivalent mortars incorporating different ratios of recycled sand

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